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American toads eat many species of pest insects and other invertebrates. They are widely considered friends to gardeners and farmers. The toxins produced by their skin may eventually prove useful in medical research.
Positive Impacts: research and education; controls pest population
The main predators of American toads are snakes. One species, eastern hognose snakes, specializes on eating toads. Some snakes, such as garter snakes, are immune to the poisonous glands of American toads. When these toads are faced with a predator that is immune to their poison they will sometimes urinate on themselves to become a less attractive meal. They also inflate their bodies with air to make themselves more difficult for a snake to swallow.
Female toads prefer to lay their eggs in ponds without fish. The eggs they lay are countershaded: lighter on the bottom and darker on the top to blend in with the background when viewed from above or below.
Tadpoles avoid predators by swimming in very shallow water, and by swimming close together in schools during the day. They also have toxic chemicals in their skin that discourage some potential predators. Metamorphosed toads are cryptically colored, and are actively mainly at night, making it harder for predators to find them.
Known Predators:
Anti-predator Adaptations: cryptic
American toads have short legs, stout bodies, and thick skins with noticeable warts. These warts can be colored red and yellow. The warty skin contains many glands that produce a poisonous milky fluid, providing these toads with excellent protection from many of their predators. This poison is only harmful if it is swallowed or if it gets in the eyes, but it can make many animals very sick.
The skin color of American toads is normally a shade of brown, but it can also be red with light patches, olive, or gray. The bellies are a white or yellow color. Toad skin color changes depending on temperature, humidity, and stress. The color change ranges from yellow to brown to black. American toads have four toes on each front leg and five toes connected together by a webbing on each hind leg. The pupils of American toads are oval and black with a circle of gold around them. The sexes can be distinguished in two ways. Males have dark colored throats, of black or brown, while females have white throats and are lighter overall. Also, female American toads are larger than male American toads. American toads are between 50 and 100 mm in length but are usually around 75 mm. American toads can be distinguished from other species of toads by the presence of several dark spots on their backs which contain only one or two warts each. These black spots are sometimes circled with white or yellow. Some types of American toads have a prominent ridge on the top of their heads.
The eggs of American toads are black on top and white on the bottom (countershaded), and embedded in long strings of clear sticky gel. The larvae that hatch from eggs are called "tadpoles." They are dark (almost black) with smooth skin, round bodies, and a somewhat rounded tail. Like adult toads, larvae have defensive chemicals in their skin. They grow to over a centimeter in length before transforming. Newly-metamorphosed toadlets are usually 0.8 and 1.3 cm long when they first emerge. Their coloration is similar to that of adult toads.
Range length: 50 to 102 mm.
Average length: 75 mm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry ; poisonous
Sexual Dimorphism: female larger; sexes colored or patterned differently
In the wild most American toads probably don't survive more than a year or two. The majority die before transforming from tadpoles into toadlets. However, they are capable of living much longer. Some toads have lived longer than 10 years in the wild. There is a documented account of a captive toad that lived to the ripe old age of 36 and was killed by mistake.
Range lifespan
Status: wild: 0 to 10 years.
Average lifespan
Status: wild: < 1 years.
Range lifespan
Status: captivity: 0 to 36 years.
American toads require a semi-permanent freshwater pond or pool for their early development. They also require dense patches of vegetation, for cover and hunting grounds. Given these two things and a supply of insects for food, American toads can live almost everywhere, ranging from forests to backyards. They are common in gardens and agricultural fields. During daylight hours they seek cover beneath porches, under boardwalks, flat stones, boards, logs, wood piles, or other cover. When cold weather comes, these toads dig backwards into their summer homes or may choose another site in which to hibernate.
Habitat Regions: temperate ; terrestrial ; freshwater
Terrestrial Biomes: chaparral ; forest ; rainforest ; scrub forest ; mountains
Aquatic Biomes: lakes and ponds; rivers and streams
Wetlands: marsh ; swamp ; bog
Other Habitat Features: urban ; suburban ; agricultural ; riparian
American toads, Anaxyrus americanus, are only native to the Nearctic region. They are found throughout large portions of North America, from northern Chihuahua in Mexico, northward to James Bay in Canada and eastward from the Imperial Valley of California and the Columbia River Valley in Washington and Oregon to the Atlantic coast from Florida to southern Quebec. They are generally not present in the most southern states or, if they are, only in the northern part. These toads have an immense ability to adapt to their surroundings as long as there is a source of semi-permanent water for them to use in the breeding season. This quality has allowed them to successfully colonize suburban and agricultural areas.
Biogeographic Regions: nearctic (Native )
Adult American toads are carnivores, but toad tadpoles are considered herbivores, because they graze on aquatic vegetation (algae).
Adult American toads are generalists. They eat a wide variety of insects and other invertebrates, including snails, beetles, slugs, and earthworms. Unlike most toads, who wait for prey to come along and pounce on it, American toads can shoot out their sticky tongues to catch prey. They also may use their front legs in order to eat larger food. They grasp their food and push it into their mouths. One American toad can eat up to 1,000 insects every day.
Toads do not drink water but soak it in, absorbing moisture through their skin.
Animal Foods: insects; terrestrial non-insect arthropods; terrestrial worms
Plant Foods: algae
Primary Diet: carnivore (Eats non-insect arthropods); herbivore (Algivore)
American toads are responsible for controlling the populations of many kinds of insects. The number of insects they eat makes them a crucial part of controlling these populations.
There are no negative impacts of American toads on humans.
Female American toads lay their eggs in freshwater. Hatching occurs 3 to 12 days after laying, depending on the temperature of the water. The tadpoles group together and feed and grow for 40 to 70 days.
When the tadpoles hatch they have gills located on the sides of their heads just posterior to their mouths. During the first 20 days the tadpoles start to form their hind legs. The legs grow slowly, but continuously. After 30 to 40 days the front legs, which were previously covered by a layer of skin, appear. At the same time that the front legs emerge, the tadpoles' gills disappear, and the tadpoles start to breathe "atmospheric" air. Between the last two or three days of development, they complete their metamorphosis, resorbing their tails and strengthening their legs. They also stop eating plants in favor of animal matter.
Newly-metamorphosed toads stay near their pond for a few days (or longer if the climate is dry), and then disperse and begin to live primarily on land. American toads continue to grow until they reach their full adult size of approximately 75 mm.
American toads, while still growing, shed their external skin every couple of weeks or so. Older frogs lose their skin around four times yearly. The skin peels off in one piece, and is collected under its tongue, where it is then gulped down.
Development - Life Cycle: metamorphosis
American toads have no special conservation status, as they are still common in most of their range. Some populations have declined in recent years, possibly due to pollution.
US Migratory Bird Act: no special status
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
American toads have one of the most notable calls of all toads. They give off long trill sounds that each last between 4 and 20 seconds. American toads use this call as a way to attract females for breeding. Their calls become frantic, loud, and constant during mating season. Many young males continue to call late into the summer. When they call, their throats puff out like large, inflatable balloons.
American toads also use body postures, touch, and chemical cues for communicating.
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: choruses
Perception Channels: visual ; tactile ; acoustic ; chemical
American toads are the most widespread toad species in North America.
There are two subspecies of American toads, eastern and dwarf. Dwarf American toads live mainly in the west, eastern American toads live in the eastern portions of the range.
Contrary to folk-belief, you will not get warts if you touch a toad. However, the defensive chemicals in toad skin are toxic to humans, so its important to wash one's hands carefully after handling one.
Breeding occurs in the months of March or April, but may extend into July. It usually triggered by warming temperatures and longer days. The males always arrive on the mating grounds well ahead of females. They congregate in shallow wetlands, ponds, lakes and slow-moving streams. After finding a suitable area, the male toads establish territories and begin calling the females. Females may choose their mates by assessing the males' breeding calls as well as the quality of the defended breeding territory.
Male toads get dark horny pads on their first and second two toes on their forelegs. This helps them close their front limbs around a female's abdomen in a posture called "amplexus". Once a female comes close, any nearby male will attempt to mate with her. The male holds on to the female, and she moves to a suitable location in the water to lay eggs. When she releases her eggs, he releases sperm to fertilize them (like most frogs and toads, fertilization is external).
Mating System: polygynous ; polygynandrous (promiscuous)
After mating takes place, the females lay their eggs in the water, in long spiral tubes of jelly. They lay 4000 to 8000 eggs in two rows. When each row of eggs is stretched it generally measures between between six and twenty meters long (20 to 66 ft.). Each individual egg is 1.5 mm in diameter. The eggs mature fastest at higher temperatures. They generally hatch in 3 to 12 days. After developing for 40 to 70 days, the tadpoles transform into adults. This usually takes place from June to August, depending on location. They reach sexual maturity at around 2 to 3 years of age.
Breeding interval: American toads breed from once yearly.
Breeding season: American toads breed from March to July each year, depending on location.
Range number of offspring: 4000 to 8000.
Range time to hatching: 2 to 14 days.
Range age at sexual or reproductive maturity (female): 2 to 3 years.
Range age at sexual or reproductive maturity (male): 2 to 3 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous
Female toads provide nutrients for their eggs inside their bodies. Once the eggs are laid and fertilized, the parents ignore them.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female)
The American toad (Anaxyrus americanus)[2] is a common species of toad found throughout Canada and the eastern United States. It is divided into three subspecies: the eastern American toad (A. a. americanus), the dwarf American toad (A. a. charlesmithi) and the rare Hudson Bay toad (A. a. copei). Recent taxonomic treatments place this species in the genus Anaxyrus instead of Bufo.[2][3][4]
The eggs of the American toad are laid in two strings and can hatch in 2–14 days. When hatched the tadpoles are recognizable by their skinny tails in relation to the size of their black bodies. They may advance to adulthood in 50–65 days. When metamorphosis is completed, the "toadlets" may stay in the water for a short period of time before they become mostly land based. Often entire groups of tadpoles reach the toadlet stage at once and a mass migration to higher ground takes place usually to shaded areas of mid range and upland forests bordering the marshes from where they bred. Toadlets can be observed eating microscopic bugs as fast as they can in the ground area they roam between various vegetation; they are also known to eat ants, spiders, slugs and worms. Studies have shown that they have a mutualistic relationship with Chlorogonium algae, which makes tadpoles develop faster than normal. The type of leaf litter impacts the amount of American toad tadpoles in a location. Leaf litter type did not have an effect on tadpole survival. Some leaf litter even had effect on parasites Purple loosestrife led to decreased parasite survival[5]
Tadpoles have several mechanisms to reduce predation.[6] They avoid predators by swimming in very shallow water often with thick grass vegetation, and by swimming close together in schools during the day. Tadpoles also produce toxic chemicals in their skin that discourage some potential predators. Fish have been reported to die after consuming one tadpole; however, most fish quickly learn to avoid eating American toad tadpoles. The tadpoles are also very small and they are a solid black color.[7]
Based on DNA sequence comparisons, Anaxyrus americanus and other North American species of Anaxyrus are thought to be descended from an invasion of toads from South America prior to the formation of the Isthmus of Panama land bridge, presumably by means of rafting.[8]
Races tend to hybridize with Anaxyrus woodhousii in their overlapping ranges.
The eastern American toad (A. a. americanus) is a medium-sized toad usually ranging in size from 5–9 cm (2.0–3.5 in);[9] record 11.1 cm (4.4 in).[10] The color and pattern is somewhat variable, especially for the females. Skin color can change depending on habitat colors, humidity, stress, and temperature. Color changes range from yellow to brown to black, from solid colors to speckled. Their breeding habits are very similar to Anaxyrus fowleri. The call or voice of a breeding male is a high trill, lasting 6–30 seconds,[10] similar to a ringing telephone. Males call for an average of 6-7 nights during their breeding period.[11] Females show preference for call efforts(rate × duration), but not call frequency.[12] They hibernate during the winter. The eastern American toad has spots that contain only one to two warts. It also has enlarged warts on the tibia or lower leg below the knee. While the belly is usually spotted, in some areas many are, and it is generally more so on the forward half (in some rare individuals there may be few or no spots). This subspecies of the American toad has no or very little markings on it. The spades on the back legs are blackish. Some toads of this subspecies have a more pervasive red and deep brown color, many with red warts on their bodies. Also eastern American toads have parotoid glands that are the same color as the surrounding skin. The glands don't usually have any patterning on them.
Other species that may be confused with the eastern American toad are Fowler's toad, which has three or more warts in the largest dark spots, and in the far west of its range woodhouse's toad. Fowler's toad can be especially difficult to identify in comparison to the eastern American toad but one difference is that it never has a spotted belly and both cranial crests touch the parotoid glands. Also, Fowler's toads are very fast hoppers (bursts of 5–10 fast hops) in comparison to Eastern toads lethargic, casual hopping and walking locomotion. In the eastern American toad these crests almost never touch the parotoid glands, which secrete bufotoxin, a poisonous substance meant to make the toad unpalatable to potential predators. Bufotoxin is a mild poison in comparison to that of other poisonous toads and frogs, but it can irritate human eyes and mucous membranes[13] and is dangerous to smaller animals (such as dogs) when ingested.[14]
American toads require a semi-permanent freshwater pond or pool with shallow water in which to breed, to gather their water supplies in times of drought or as a routine,[10] and for their early development. They also require dense patches of vegetation, for cover and hunting grounds. Given these two things and a supply of insects for food, American toads can live almost everywhere, ranging from forests to flat grassland. Females when caught are silent and easily tamed, adapting to terrarium life readily, while the smaller males are readily communicative. The smaller males do not adapt well to terrarium life and should be released after a few days of observation. Adult toads are mostly nocturnal, although juveniles are often abroad by day. When it rains, these toads will become active and can be observed eating robustly worms and insects leaving their burrows and walking in front of an opportunist toad. These toads are 'creatures of habit' once they have a certain area they prefer to live within... an acre of wooded forest with water in proximity for soaking, a home with cool ledges and window wells; they commonly seek cover in burrows, under boardwalks, flat stones, boards, logs, wood piles, or other cover. When cold weather comes, these toads dig backwards and bury themselves in the dirt of their summer homes, or they may choose another site in which to hibernate.[7] Their diet includes crickets, mealworms, earthworms, ants, spiders, slugs, centipedes, moths, and other small invertebrates. Some of these toads have been known to live over 30 years and currently a female specimen (over 13 centimeters long) is living healthily into her late 30s. Another female toad of 17 centimeters is known to have existed in Wisconsin from Washington Island on Lake Michigan.
The eastern American toad may be confused with the Canadian toad in the area where they overlap, but the cranial crests in the American toad do not join to form a raised "boss" (bump) like they do in the Canadian toad. Its range also overlaps with the southern toad's, but in this species the cranial crests form two unique knobs.
The dwarf American toad (A. a. charlesmithi), is a smaller version of the American toad, which reaches lengths of about 6 cm (2+1⁄4 in), is generally a dark reddish color ranging to light red in some specimens in isolated populations. The spots on the back are reduced or absent, and when present they contain a few small red warts and a black ring around it like in the normal American toad. The warts are always darker than the skin of the toad. Some specimens have a white dorsal line in the middle of their backs. The ventral surface or belly is usually cream colored with a few dark spots in the breast area. This subspecies can be distinguished from the above-mentioned species in the same manner as for the eastern American toad. The southwestern portion of the Dwarf American toad's range overlaps with that of the Gulf Coast toad. The latter species is distinguished by the presence of a dark lateral stripe as well as a deep "valley" between its prominent cranial crests. It eats mainly spiders, worms and small insects.
The Hudson Bay toad (A. a. copei) is a rare Canadian subspecies of A. americanus.[15] This subspecies of the American toad has been seen in the northern parts of Ontario where there are a few isolated populations. These northern dwarf toads mostly have the red coloring on the sides of their bodies and have an unusually high number of warts for the subspecies. Interbreeding with eastern American toads caused this subspecies to lose the red coloring on their backs.
Toads display breeding site fidelity, as do many other amphibians. Individuals that return to natal ponds to breed will likely encounter siblings as potential mates. Although incest is possible, Anaxyrus americanus siblings rarely mate.[16] These toads likely recognize and actively avoid close kins as mates. Advertisement vocalizations by males appear to serve as cues by which females recognize their kin.[16]
Newly metamorphosed American Toad (~5mm) at confluence of Keay Brook, Berwick, ME and the Salmon Falls River.
Approximately one week into adult cycle, shown in comparison to an adult female human hand
Eastern American toad, seen from behind, shows characteristic markings and "warts"
Closeup of the Eastern American toad
Young American toad
Front view of Eastern American toad
Side view of camouflaged A. americanus
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Eastern American toad (A. a. americanus), North Dumfries, Ontario
American toad eating its skin as it sheds
American toad chirp - mating call
American toad feeding time
5 year old female American toad.
A closeup of an Eastern American toad seen in Tennessee.
{{cite journal}}: Cite journal requires |journal= (help) The American toad (Anaxyrus americanus) is a common species of toad found throughout Canada and the eastern United States. It is divided into three subspecies: the eastern American toad (A. a. americanus), the dwarf American toad (A. a. charlesmithi) and the rare Hudson Bay toad (A. a. copei). Recent taxonomic treatments place this species in the genus Anaxyrus instead of Bufo.
La Amerika bufo (Anaxyrus americanus, iam Bufo americanus[1]) estas ofta specio de bufo kiu troviĝas tra orientaj Usono kaj Kanado. Ĝi estas dividata en tri subspecioj — nome la orienta Amerika bufo (A. a. americanus), la nana Amerika bufo (A. a. charlesmithi), kaj la rara bufo de la Hudsona Golfo (A. a. copei). Ĵusaj taksonomiaj traktadoj lokigas tiun specion en la genron Anaxyrus anstataŭ en la genro Bufo.[2][3][4]
Proksimume unusemajnulo, montranta kompare al ina plenkreskulo.
Tiu plenkreskulo estis trovita en sudorienta Idaho, malofta loko por tiu specio. La folioj montras la relativan grandon de la bufo.
Orienta Amerika bufo, vidata el malantaŭo, montras karakterajn markojn kaj "verukojn".
Detalo de orienta Amerika bufo.
Juna Amerika bufo.
Frontaĵo.
Fronta vido de orienta Amerika bufo.
Flanka vido de kamufla A. americanus
Orienta Amerika bufo. (A. a. americanus), Nordaj Dumfries, Ontario
Amerika bufo manĝanta sian haŭton dum tiu eliĝiĝas.
La Amerika bufo (Anaxyrus americanus, iam Bufo americanus) estas ofta specio de bufo kiu troviĝas tra orientaj Usono kaj Kanado. Ĝi estas dividata en tri subspecioj — nome la orienta Amerika bufo (A. a. americanus), la nana Amerika bufo (A. a. charlesmithi), kaj la rara bufo de la Hudsona Golfo (A. a. copei). Ĵusaj taksonomiaj traktadoj lokigas tiun specion en la genron Anaxyrus anstataŭ en la genro Bufo.
El sapo americano (Anaxyrus americanus) es una especie de anfibio anuro perteneciente a la familia Bufonidae.[2] Es propio de América del Norte.
Los renacuajos pueden alcanzar la edad adulta en 30-40 días. Al finalizar, los sapos jóvenes pueden permanecer en el agua durante un corto período de tiempo antes de que la tierra se convierta en su hogar. Una relación de mutualismo con el alga Chlorogonium se ha estudiado, lo que hace que los renacuajos se desarrollen más rápidamente de lo normal.[cita requerida]
Los renacuajos tienen varios mecanismos para reducir la depredación. Evitan a los depredadores nadando en aguas poco profundas y permaneciendo junto a los demás durante el día. Los renacuajos también producen sustancias químicas tóxicas en su piel que desaniman a algunos depredadores potenciales. Se ha informado de peces muertos luego de haber consumido renacuajos; sin embargo, la mayoría de los peces aprenden rápidamente a evitar el consumo de renacuajos.[cita requerida]
Se reconocen las siguientes subespecies:[3]
El sapo americano (Anaxyrus americanus) es una especie de anfibio anuro perteneciente a la familia Bufonidae. Es propio de América del Norte.
Anaxyrus americanus Anaxyrus generoko animalia da. Anfibioen barruko Bufonidae familian sailkatuta dago, Anura ordenan.
Anaxyrus americanus, le Crapaud d'Amérique, est une espèce d'amphibiens de la famille des Bufonidae[1].
Cette espèce se rencontre dans l'est de l'Amérique du Nord[1],[2] :
Elle a été introduite à Terre-Neuve.
Le crapaud d'Amérique à des pustules sur le dos et des glandes en dessous derrière ses yeux. Leurs yeux sont sur les côtés. Ils ont aussi une ligne dorsale et quatre doit à leurs mains. Les crapaud d'Amérique peuvent être brun, rougeâtre ou verdâtre. Les mâles mesurent de 54 à 85 mm et les femelles de 56 à 110 mm[2]. Les femelles pondent de 4 000 à 8 000 œufs[2]. Les têtards de cette espèce sont connus pour avoir une relation symbiotiques avec des algues du genre Chlorogonium[3]. Le crapaud d’Amérique vit en moyenne 1 à 2 ans, éventuellement plus en captivité.
Anaxyrus americanus pond ses œufs entre les mois d'avril et juillet[4], surtout fin avril[5]. Les principaux sites de reproduction sont de petits fossés, de petits étangs ou des cours d'eau lents et peu profonds. Le mâle saisit la femelle derrière ses pattes avant et elle commence à pondre ses œufs[6].
Chaque ponte comporte de 4 000 à 8 000 œufs. L'éclosion survient après 3 à 12 jours d'incubation. Les têtards sont de couleur sombre, presque noire. Après leur métamorphose, les jeunes crapauds migrent en masse loin de l'eau[5].
Cette espèce a été décrite sous le nom de Bufo americanus, elle a été placée dans le genre Anaxyrus par Frost et al. en 2006[7]. Cependant elle reste parfois nommée Bufo americanus. Deux sous-espèces sont reconnues par Masta et al. en 2002[8] Anaxyrus americanus charlesmithi et Anaxyrus americanus americanus. En 2011, Fontenot, Makowsky et Chippindale[9] considèrent Anaxyrus charlesmithi comme une espèce de plain rang.
Bufo americanus americanus, la vue de dos montre des marques et des "pustules" caractéristiques.
Bufo americanus americanus vu de près.
Juvénile, probablement Bufo americanus charlesmithi.
Vue de face de Bufo americanus charlesmithi.
Bébé crapaud d'Amérique
Anaxyrus americanus, le Crapaud d'Amérique, est une espèce d'amphibiens de la famille des Bufonidae.
Il rospo americano (Anaxyrus americanus (Holbrook, 1836)) è un anfibio della famiglia Bufonidae, nativo degli Stati Uniti d'America e del Canada.[2]
Il rospo americano (Anaxyrus americanus (Holbrook, 1836)) è un anfibio della famiglia Bufonidae, nativo degli Stati Uniti d'America e del Canada.
De Amerikaanse pad[2] (Anaxyrus americanus of Bufo americanus) is een kikker uit de familie padden (Bufonidae).[3]
Zowel de Nederlandstalige naam 'Amerikaanse pad' als de wetenschappelijke soortnaam americanus verwijzen naar het verspreidingsgebied dat bestaat uit delen van Noord-Amerika.
De soort werd voor het eerst wetenschappelijk beschreven door John Edwards Holbrook in 1836. Oorspronkelijk werd de wetenschappelijke naam Bufo americanus gebruikt. De soort behoorde lange tijd tot het geslacht Bufo waardoor deze naam in de literatuur veel wordt gebruikt.
De mannetjes worden ongeveer 8,5 centimeter lang, de vrouwtjes worden groter tot 11 cm.[4] De lichaamskleur is variabel, de meeste exemplaren zijn bruin tot grijs maar ook roodachtige tot groene kleuren komen voor. De gehele bovenzijde van het lichaam is bedekt met kleine gele tot rode wratjes, met hier en daar een donkere tot zwarte vlek. Het oppervlak van deze vlekken is nooit groter dan de afstand tussen enkele ratten. Hiermee is de Amerikaanse pad van andere soorten binnen het areaal te onderscheiden.[5] Andere soorten, zoals Anaxyrus fowleri, hebben veel grotere vlekken op het lichaam.
Deze soort lijkt wel op de in Europa algemeen voorkomende gewone pad (Bufo bufo) maar het lichaam is meer gedrongen en is bijna rond, ook zijn de poten korter.[4]
De kop is afgerond en stomp, de ogen hebben een goudgele kleur en een horizontale pupil. De ogen zijn groot en zijn hoog op de kop geplaatst. Het trommelvlies of tympanum is relatief groot en duidelijk te zien.
Het menu bestaat uit kleine ongewervelden zoals insecten en wormen. De Amerikaanse pad is nachtactief en overdag verstopt hij zich onder stenen of bladeren om tijdens de schemering te ontwaken. Belangrijke vijanden zijn reptielen als slangen, roofvogels zoals haviken en uilen en ten slotte rovende zoogdieren zoals wasberen, stinkdieren en dassen.[5]
Als de pad verstoord wordt, houdt het dier zich dood door zich op de rug te draaien en zich enige tijd niet te bewegen. De belangrijkste vorm van verdediging bestaat uit de gifklieren in de huid en met name de parotoïden achter de ogen. Deze gepaarde klier is duidelijk te zien en wordt wel de oorklier genoemd.
De larven van veel Amerikaanse paddensoorten zijn giftig, en de Amerikaanse pad is hierop geen uitzondering. Ze zijn zo giftig dat de vissen die in de natuurlijke habitat voorkomen het verschil weten tussen een boomkikkerlarve en een paddenlarve. Boomkikkerlarven worden door de vissen buitgemaakt terwijl de paddenlarven met rust wordt gelaten.
De Amerikaanse pad komt voor in zuidoostelijk Canada tot in de Verenigde Staten, ten oosten van de Rocky Mountains tot de Atlantische kust in Mexico. De pad houdt van vochtige en dichtbegroeide biotopen en kan dus in veel gebieden terecht; bossen, graslanden, heidevelden en moerassen, liefst met een strooisellaag waar in gescholen en gejaagd kan worden. In de paartijd is voor de voortplanting oppervlaktewater nodig, maar de kleinste watertjes voldoen. Deze soort is dan ook niet sterk aan water gebonden, maar is meestal niet ver van een bron te vinden. Warmere plaatsen hebben de voorkeur en de ideale dagtemperaturen liggen rond de 23 graden Celsius, de watertemperatuur rond de 20 graden. Zoals alle padden drinkt deze soort niet maar wordt water door de huid opgenomen als de pad met water in contact komt.
Ook in door de mens aangepaste habitats zoals parken en tuinen zijn een geschikt leefgebied. De pad wordt in zijn natuurlijke verspreidingsgebied gewaardeerd door tuinders vanwege het menu dat uit insecten bestaat. De pad graaft holletjes waarin overdag geschuild wordt en is ook wel onder stenen te vinden.
De bonte kleuren en duidelijk zichtbare 'wratten' op de rugzijde.
Een juveniel met een kenmerkende rode kleur.
Voorzijde van waarschijnlijk ondersoort B. a. charlesmithi.
Bufo americanus americanus
De Amerikaanse pad (Anaxyrus americanus of Bufo americanus) is een kikker uit de familie padden (Bufonidae).
Anaxyrus americanus (antigamente Bufo americanus), também conhecido por Sapo-americano é uma espécie de sapo encontrada em todo o leste dos Estados Unidos e Canadá.
A classificação da espécie relativa ao risco de extinção (estado de conservação) é considerada "pouco preocupante".[1]
Anaxyrus americanus (antigamente Bufo americanus), também conhecido por Sapo-americano é uma espécie de sapo encontrada em todo o leste dos Estados Unidos e Canadá.
A classificação da espécie relativa ao risco de extinção (estado de conservação) é considerada "pouco preocupante".
Amerikansk padda (Anaxyrus americanus) är en nordamerikansk paddart i släktet Anaxyrus. Den fördes tidigare till släktet Bufo.
En medelstor padda, längden är 5 till 10 cm. Medellängden är omkring 7,5 cm, och medelvikten drygt 20 gram. Ryggen är brunaktig, röd, grönaktig eller ljusgrå med mörka fläckar, som innehåller en eller två vårtor var. Likt många paddor har ryggen ett flertal körtlar som producerar en mjölkaktig, giftig utsöndring. Buken är blekgul till vit. Hanarna har mörk strupe, medan honorna har ljus. De senare är också något större än hanarna. Buksidan, och hos honorna även halsen är ljusa. Pupillen är oval och vertikal.[2]
Den amerikanska paddan är uppdelad i två underarter, Anaxyrus americanus americanus och Anaxyrus americanus charlesmithi. Den senare underarten känns igen på att den är mindre, rödaktigare i färgen, och att buken saknar fläckar, medan buken hos nominatunderarten ofta är kraftigt fläckig.[3]
Den amerikanska paddan finns i östra och centrala Nordamerika från Labrador, området kring Hudson Bay samt Manitoba till norra Texas, Louisiana, centrala Alabama, norra Georgia och North Carolina.[1]
Paddan föredrar områden med tät markvegetation, inte allt för långt från vattensamlingar där den kan leka, men kan i övrigt återfinnas i många olika miljöer som skogar, prärier, odlade områden och trädgårdar. De är inaktiva under dagen och söker då skydd under flata stenar, träbitar, utomhustrappor och liknande. Under vintern söker den upp liknande gömslen för att gräva ner sig och övervintra.[2]
Paddorna lever av insekter och andra ryggradslösa djur.[2]
Lek och larvutveckling sker i stillastående eller långsamrinnande vattensamlingar, permanenta eller temporära, gärna med få fiskar.[1] Honan lägger äggen i form av långa, ihopflätade band, eller klara, geléaktiga klumpar.[2]
Anaxyrus americanus americanus
Wikimedia Commons har media som rör Amerikansk padda.
Amerikansk padda (Anaxyrus americanus) är en nordamerikansk paddart i släktet Anaxyrus. Den fördes tidigare till släktet Bufo.
Загальна довжина досягає 5—11,1 см. Голова помірного розміру. Тулуб дещо витягнутий. Паротиди відокремлені від кісткових гребенів позаду очей або з'єднані з ним короткою шпорою. Паротиди витягнуті. Заочноямкові гребені високі, без вираженого здуття. Шкіра спини вкрита великою кількістю дрібних та середніх бородавок. Бородавки розвинені також на спинній стороні гомілки. Характерною особливістю є невеликі темні плями на спині з сильно збільшеними бородавками.
Забарвлення коливається від жовтувато-коричневого до бурого. З боків є зеленуватий малюнок. Бородавки зазвичай червонуваті або коричневі.
Населяє різні місцини: від приміських ландшафтів до гірських пустель. Тримається поблизу водойм, воліючи вологі укриття та схованки. Живляться комахами та іншими безхребетними.
Самиці відкладають до 2000 ікринок. Личинки з'являються через 2—14 дні. Пуголовки доволі швидко ростуть. Метаморфоз триває 50—65 днів.
Поширена від провінції Монітоби (Канада) до північного Техасу уздовж всього східного узбережжя США, ізольована популяція живе на о.Ньюфаундленд.
Anaxyrus americanus (tên tiếng Anh: American toad, "cóc Mỹ"), danh pháp đồng nghĩa Bufo americanus[3]) là một loài cóc thường gặp sinh sống ở khắp miền đông Hoa Kỳ và Canada. Có ba phân loài A. a. americanus, A. a. charlesmithi, và A. a. copei. Theo nghiên cứu phân loại, loài này thuộc về chi Anaxyrus, chứ không phải Bufo.[3][4][5]
Anaxyrus americanus (tên tiếng Anh: American toad, "cóc Mỹ"), danh pháp đồng nghĩa Bufo americanus) là một loài cóc thường gặp sinh sống ở khắp miền đông Hoa Kỳ và Canada. Có ba phân loài A. a. americanus, A. a. charlesmithi, và A. a. copei. Theo nghiên cứu phân loại, loài này thuộc về chi Anaxyrus, chứ không phải Bufo.
Bufo americanus Holbrook, 1836[1]
Синонимы
Американская жаба[2] (лат. Bufo americanus[1]) — земноводное семейства настоящих жаб.
Общая длина достигает 5—11,1 см. Голова умеренного размера. Туловище немного вытянутое. Паротиды вытянутые, отделены от костных гребней позади глаз, или соединены с ними короткой шпорой. Заглазничные гребни высокие, без выраженного вздутия. Кожа спины покрыта большим количеством мелких и средних бородавок. Бородавки развиты также на спинной стороне голени. Характерной особенностью являются небольшие тёмные пятна на спине с сильно увеличенными бородавками.
Окраска варьирует от желтовато-коричневого до бурого цвета. По бокам имеется зелёный рисунок. Бородавки обычно красноватые или коричневые.
Населяет различные биотопы от пригородных ландшафтов до горных пустынь. Держится вблизи водоёмов, предпочитая влажные укрытия и убежища. Питается насекомыми и другими беспозвоночными.
Самка откладывает до 2000 икринок. Личинки появляются через 2—14 дней. Головастики довольно быстро растут. Метаморфоз длится 50—65 дней.
Вид распространён от провинции Манитобы (Канада) до северного Техаса вдоль всего восточного побережья США, изолированная популяция живёт на острове Ньюфаундленд.
Американская жаба (лат. Bufo americanus) — земноводное семейства настоящих жаб.
Общая длина достигает 5—11,1 см. Голова умеренного размера. Туловище немного вытянутое. Паротиды вытянутые, отделены от костных гребней позади глаз, или соединены с ними короткой шпорой. Заглазничные гребни высокие, без выраженного вздутия. Кожа спины покрыта большим количеством мелких и средних бородавок. Бородавки развиты также на спинной стороне голени. Характерной особенностью являются небольшие тёмные пятна на спине с сильно увеличенными бородавками.
Окраска варьирует от желтовато-коричневого до бурого цвета. По бокам имеется зелёный рисунок. Бородавки обычно красноватые или коричневые.
Населяет различные биотопы от пригородных ландшафтов до горных пустынь. Держится вблизи водоёмов, предпочитая влажные укрытия и убежища. Питается насекомыми и другими беспозвоночными.
Самка откладывает до 2000 икринок. Личинки появляются через 2—14 дней. Головастики довольно быстро растут. Метаморфоз длится 50—65 дней.
Вид распространён от провинции Манитобы (Канада) до северного Техаса вдоль всего восточного побережья США, изолированная популяция живёт на острове Ньюфаундленд.
美國蟾蜍（學名：Bufo americanus），又名美洲蟾蜍，是一種在美國東部及加拿大很普遍的蟾蜍。
美國蟾蜍會生兩串的卵，只要3-13日就會孵化。蝌蚪孵化時的尾巴相對於身體很幼。它們生長30-40日就會變成蟾蜍，最初的短時間還會留在水中，但隨後就會陸上生活。蝌蚪會與綠梭藻有共生關係，它們可以幫助蝌蚪快些成長。
蝌蚪有多種方法來避免掠食。[2]它們會游到非常淺水區及聚集在一起來避開掠食者。它們也會分泌出有毒的物質。有指魚類曾吃下蝌蚪而死亡，但它們已學懂避免掠食這些蝌蚪。[3]
美國蟾蜍指名亞種（B. a. americanus）是一種中等體型的蟾蜍，長5-9厘米。身體顏色及式樣多變。它們會於冬天冬眠。身體上的斑點上包含1-2個疙瘩。在脛骨位置有較大的疙瘩。腹部一般都有斑點，前端較多。
其他容易與指名亞種混淆的物種包括福勒蟾蜍及庭園蟾蜍。福勒蟾蜍很難與美國蟾蜍分辨，它們腹部沒有斑點，顱冠接觸腮腺。美國蟾蜍的顱冠完全不接觸腮腺。它們所分泌的毒素的毒性相對較溫和，但也可以刺激人類皮膚及對細小的動物有危險。
美國蟾蜍需要半永久的淡水湖來進行高期發育。它們需要密林來覆蓋作保護。只有滿足這兩項條件及有足以的食物供應，它們可以棲息在任何地方。美國蟾蜍在花園及農地也很普遍。日間它們會躲在門廊、木板人行道、石底、木柱等。冬天時，它們會挖穴將自己藏起或尋找另一地方冬眠。[2]它們會吃蟋蟀、黃粉蟲、蚯蚓、螞蟻、蜘蛛、蛞蝓、百足及其他細小的脊椎動物。
矮體亞種（B. a. charlesmithi）是較為細小的亞種，長約6厘米及呈暗紅色。背上的斑點已經退化，若有也只有1個疙瘩。腹部呈奶白色，胸部有些少暗色的斑點。它們可以與上述的物種以同樣方法分辨。分佈在西南部份的會與B. nebulifer重疊分佈地。它們主要吃蜘蛛、蠕蟲及細小的昆蟲。
赫德亞種（B. a. copei）是美國蟾蜍的加拿大稀有亞種。
分類 界 : 動物界 Animalia 門 : 脊索動物門 Chordata 亜門 : 脊椎動物亜門 Vertebrata 綱 : 両生綱 Amphibia 目 : 無尾目 Anura 亜目 : カエル亜目 Neobatrachia 科 : ヒキガエル科 Bufonidae 属 : ヒキガエル属 Bufo 種 : アメリカヒキガエルアメリカヒキガエル（亜米利加蟇蛙、Bufo americanus）は、ヒキガエル科ヒキガエル属に分類されるカエル。未判定外来生物。
種小名americanusは「アメリカの」の意で、和名や英名と同義。
体長5-11cm。体色は褐色だが、黒や赤の個体もおり変異が大きい。背面には不規則な暗色の斑紋が入り、正中線上に明色の筋模様が入る個体もいる。皮膚は疣状の突起で覆われる。
草原や森林、農耕地、民家近く、都市部等幅広い環境に生息する。陸棲で繁殖期以外に積極的に水場に近づくことはない。夜行性で、昼間は石や倒木の下等で休む。
食性は動物食で、昆虫類や節足動物、甲殻類、陸棲の貝類、ミミズ等を食べる。素早く舌をのばして獲物を捕らえ飲みこむ。
繁殖形態は卵生で、3-7月に池沼の水草や石の下等に長いひも状の寒天質に包まれた1回に4000-8000個の卵を産む。
ペットとして飼育されることもあり、日本にも輸入されていた。しかし2005年に外来生物法により本種を含めたヒキガエル属が未判定外来生物に指定されたため2007年現在輸入は停止している。
この項目は、動物に関連した書きかけの項目です。この項目を加筆・訂正などしてくださる協力者を求めています（Portal:生き物と自然／プロジェクト:生物）。 
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